Tese de dout., Psicologia, Faculdade de Ciências Humanas e Sociais, Univ. do Algarve, 2011; In this thesis, we present six studies that investigated the role of color information during visual object recognition. The interactions between surface color and color knowledge information were investigated in two studies (chapters 2 and 3). In chapters 4 and 5, we present data that identify the visual processing stage at which color information improves color and non-color diagnostic object recognition. In chapter 6, the neural pathways supporting color object recognition were investigated. Additionally, in an attempt to bring some consistency to the literature, we performed a systematic meta-analysis on the effects of color on object recognition in chapter 7.
Chapter 2 and 3 provided data suggesting that surface color information is more influential than color knowledge information during object recognition. Chapter 4 and 5 showed that color information improves the recognition of color and non-color diagnostic objects at different stages of visual processing. Although color information is an important cue for both of these types of objects in the early visual processes, it is also important in later stages of visual processing for color diagnostic object recognition. In chapter 6...

The use of digital photography is migrating from the major applications in pho
tojournalism to professional studio photography. Traditional service bureaus such
as professional photo labs and prepress trade shops are adding digital imaging
services to their film-based services. Also, businesses such as advertising agencies
and publishers, who traditionally outsource work to service bureaus, are bringing
digital imaging services in-house. State of the art imaging technology empowers
users with new tools, but does not guarantee that the task of generating accept
able image reproductions will be easier.
The basic problem in the desktop color prepress environment is that each com
ponent in this open system handles color differently. Miscommunication between
devices results in user frustration with an unpredictable, inconsistent, and inaccurate color system. The solution to this problem is to assess one's workflow and
adopt a color management system (CMS). The purpose of CMSs is to help users
maintain color integrity throughout their desktop system and to automate the
color separation process.
This thesis project investigated the possibility of applying a comprehensive CMS
to automate the color reproduction of 3-D images procured with a digital camera.
Automatic exposure by Leaf System's Lumina digital camera and automatic
adjustments for tone reproduction...

Color matching is an important issue in the flexographic industry today because of
many problems related to it. For example, there are few standards of ink and color for
spot color printing. Further, there is no standardization in the communication among
anilox roller suppliers and their customers concerning the specific cell volume measurement of the anilox roller. This research focused on the study of the use of the banded anilox roller as a tool for color proofing under the assumption that a spot color
printed by the flexographic process actually should be produced using a banded anilox
roller as a tool for color proofing. The major questions for this study were:
1. How will the anilox cell volume and line screen per inch affect the CIE
LAB total color difference (AE) ?
2. Can the same color actually be produced with a AE < 2 (good match) by using
the same specification of anilox roller?
This research was conducted by printing a spot color with two banded anilox
rollers to match the original Pantone color as close as possible and using it for the reference. The data collected from each of the bands was plotted in diagrams to see the
effects of cell volume and line screen per inch on the total color difference(AE). In this
experiment...

Color difference equations based on the CIECAM02 color appearance model and IPT color
space have been developed to fit experimental data. There is no color space in which these
color difference equations are Euclidean, e.g. describe distances along a straight line. In this
thesis, Euclidean color spaces have been derived for the CIECAM02 and IPT color difference
equations, respectively, so that the color difference can be calculated as a simple color
distance. Firstly, the Euclidean line element was established, from which terms were derived
for the new coordinates of lightness, chroma, and hue angle. Then the spaces were analyzed
using performance factors and statistics to test how well they fit various data. The results
show that the CIECAM02 Euclidean color space has performance factors similar to the
optimized CIECAM02 color difference equation. To statistical significance, the CIECAM02
Euclidean color space had superior fit to the data when compared to the CIECAM02 color
difference equation. Conversely, the IPT Euclidean color space performed poorer than the
optimized IPT color difference equation. The main reason is that the line element for the
lightness vector dimension could not be directly calculated so an approximation was used. To
resolve this problem...

The screen printing process has been the least understood and studied
versus other imaging methods in the graphic arts industry. As equipment
configurations improve and a continuous technological development and
need for high quality output persists, this fascinating process becomes
increasingly popular in several end-use applications. Such as in packaging,
labeling, durable graphic films printing and even short run large format
halftone graphics.
There is a serious need for further deep scientific analysis of the process and
its variables. One of the poorly investigated sides of the four color screen
printing is the effect that ink placement has to the final color appearance of a
halftone print. Several known factors can influence the color result of a
screen printed image. Limitations inherent to screen printing allow for a
smaller color gamut reproduction compared to other methods, but colors are
reproduced vividly due to a uniform and high ink film thickness.
The screen - equivalent to a printing plate - consists of a stretched porous
fabric mounted on a carrier frame that is coated with a light sensitive
emulsion (stencil) and subsequently exposed and hardened at the non
image areas. The ink will flow through the screen mesh openings when
pressure and hydraulic forces are applied by a squeegee blade system.
The ink system can be cured or dried by various methods depending on its
chemistry and composition. For the specific system investigated...

Defining color tolerances numerically continues to be a topic of intense interest in colorimetry. A technique was developed to evaluate formula performance that incorporated visual uncertainty. In this technique, visual uncertainty was represented by randomized equal color-difference ellipsoids or randomized visual color differences. STRESS, a multivariate statistical tool, was employed to quantify these randomized equal color-difference ellipsoids or visual color differences. The STRESS clouds were composed of the STRESS values between the randomized equal color-difference ellipsoids and T50 equal color-difference ellipsoids, or between the randomized visual color differences and T50 visual color differences where T50 represented visually determined tolerances equivalent to an anchor-pair stimulus. These STRESS values clouds were taken as rulers to evaluate whether one color-difference formula over-, under- or well-fitted a specified color-difference dataset, based on an F-test. This technique is a necessary addition to the current deviation evaluation metrics, e.g., PF/3. In follow-on research, a Euclidean color space was developed with the color-difference formula based on IPT color space for supra-threshold color differences. The color-difference formula has similar chromatic modeling to CIE94. A lightness transformation function was applied to model color difference along lightness. A rotation matrix on the chromatic plane was also applied to achieve better characteristics of the color space. A step-wise optimization was performed to achieve better consistency and remove conflicts between different color-difference datasets. The evaluations include STRESS...

ICC color management system (CMS) has become a major tool for color image rendering and color matching in the printing and publishing industry. It attempts to automate color management functions, e.g., from scan to print, and from press sheet to proof, with the use of device profiles, a CMM, and an application programming interface. Earlier studies, conducted at RIT, showed that ICC-based digital proofing did not perform better than a well calibrated film-based proofing system. Specifically, the average AE between ICC color managed proofs and a reference press sheet was found to be 6-9 while the average AE between a film based proof and its correspondence press sheet was 5. Realizing that sources of AE errors exist in many places, e.g., printing consistency, proofer's color gamut, proofing consistency, measurement conditions, this paper discussed an improved methodology for testing the performance of color matching in a digital proofing workflow. The source profile was a SWOP press profile, supplied by Kodak, which characterizes the ANSI CGATS TR 001-1995 - Type 1 Printing condition. The destination profile was built from an Epson SC3000 ink jet printer using the Kodak Colorflow ProfileEditor at the printer's default color gamut. The IT8.7/3 basic (CMYK) target was transformed with the use of the Mac OS...

A color separation technique known as Gray Component Replacement, or GCR has
been an option available to high-end drum scanner operators for the past eight years.
Recently, GCR has been made available by lower-end color system vendors as well. GCR
consists of removing the least predominant process color ink in a unit area, reducing the
remaining colored inks by the same amount and replacing the "gray component" of the
color with black ink. One of the reported benefits of the GCR technique is that more
consistency can be realized during a pressrun. If this is in fact true, the first publication
printers who would surely utilize the technique would be newspapers. The problem of
consistency is particularly acute for newspapers. There are a number of reasons for this,
but the primary ones relate to the types of materials used. Newspapers use the cheapest
paper and ink and in many cases, they print with old or poorly maintained presses. They
would surely welcome any process that offered better reproductive quality and more
consistency, provided the investment was justifiable. Since their present color separation
systems allow for the use of GCR in the majority of cases, its potential in the area of
newspaper printing was investigated in this study.
One factor determining consistency during a pressrun is the control of ink film
thickness. As ink film thickness fluctuates...

Color transparency film is the most frequently used original material in the color
separation process. Recent technological advances in color negative film and electronic
color generated scanners capable of working from a color negative have led to new
avenues of exploration in the area of color separation. By using a color negative film as
the original it may be possible to produce color separations of equal or higher quality than
those produced from color transparencies.
This research project has investigated the possibility that a set of color separations made
from an Eastman Kodak Ektar color negative could yield a set of color separation proofs
of equal or superior quality to those made from an Eastman Kodak Kodachrome color
transparency. The attributes that were investigated were image detail, color saturation
and tone reproduction.
A total of six original scenes were photographed by the author; six using Kodachrome 25-
35mm slide film- and six using Ektar 25-35 mm negative film. Four of the original
images were photographed at the same time in a controlled studio environment. The
remaining two images were photographed outdoors to include a normal exterior scene. Twelve color separations were then generated using the Royal Zenith 210-L color
scanner. These twelve separations were then proofed using the DuPont Cromalin
proofing system.
The last stage of the study involved a visual evaluation by thirty judges with professional
experience in either the fields of photography or printing. Under standard viewing
conditions...

Test Target 4.0 (TT4.0) is the result of student teamwork to publish a technical journal for a graduate-level course titled: Advance Color Management (Course no. 2081-735-03). Offered by the School of Print Media (SPM) at Rochester Institute of Technology (RIT), the course is "a platform to experiment and to realize a new digital imaging paradigm and the dynamics of teamwork...."
Team members learn scientific methodology in process control for repeatable color as well as apply ICC-based color management practices in digital workflows. They plan and conduct press run analyses reported in TT4.0, which is printed using facilities available at RIT. In producing this publication, the team learns to integrate design, content creation, digital media, and print production in a seamless workflow.... -p. 4.; Introduction and acknowledgements / by Robert Chung - Guiding and producing a technical publication / by Edline M. Chun - A New tool for quantitative comparison of color differences / by Franz Sigg - Effect of GCR and TAC in color gamut volume / by Tiago Costa - Comparison of color gamut and amplitude responses between AM and FM screening / by Wiphut Janjomsuke - Analysis of ink dry down for hexachrome inks for sheetfed offset printing / by Nattawan Techavichien - Measuring the variation of a digital printer / by Howard Vogl - Comparing Color image capture using film transparencies and digital cameras / by Eric Berkow - A Real-world color management journey in commercial printing / by Doug Caruso - Reproducing a process color...

To analyze color errors and their sources in the color reproduction process, the reproduction is visually evaluated and compared visually with the original scene color scales and also with the original transparency viewed on a variable brightness illuminator (D5000) with an opaque reflective white surround. Graphs (press plate curves, single color proofs and END of single color proofs) have been added to the Kodak tone-reproduction diagram (1960) to obtain more complete steps in the analysis of the tone-reproduction and the color balance. The GATF Evaluation Method of Ink Color is tested and the GARC colorimetric system, which is a modified Adam’s chromatic value system, is used to analyze colorimetric measurement. The slightly dark reproduction, the shift of the color balance to bluish cyan in the reproduction; the shift of hues, the magenta toward red, the cyan and the green toward blue; and the desaturation of the blue, the cyan and the yellow are discovered as errors in the reproduction. The possible improvements of these errors are discussed.
The hope to combine the tone-reproduction analysis, the GATF Evaluation of Ink Color and the GARC colorimetric system into one system of analysis of the color errors is not fulfilled, because the mask percentages obtained from the Evaluation of Ink Color do not agree with that of the reproduction process and the hue error and grayness of the Evaluation of Ink Color do not correspond with the visual hue and the color saturation. However...

An RGB (red, green, and blue color information) workflow is used in digital photography today because a lot of the devices digital cameras, scanners, monitors, image
recorders (LVT or Light Value Technology), and some types of printers are based on
RGB color information. In addition, rapidly growing new media such as the Internet and
CD-ROM (Compact Disc-Read-Only Memory) publishing use an RGB -based monitor
as the output device. Because color is device-dependent, each device has a different
method of representing color information. Each has a different range of color they can
reproduce. Most of the time, the range of color, color gamut, that devices can produce is
smaller than that of the original capturing device. As a result, a color image reproduction
does not match accurately with its original.
Therefore, in typical color image reproduction, the task of matching a color image
reproduction with its original is a significant problem that operators must overcome to
achieve good quality color image reproduction. Generally, there are two approaches to
conquer these problems. The first method is trial-and-error in the legacy-based system.
This method is effective in a pair-wise working environment and highly depended on a
skill operator. The second method is the ICC-based (ICC or International Color
Consortium) color management system (CMS) which is more practical in the multiple
devices working environment. Using the right method leads to the higher efficiency of a digital photography produc
tion. Therefore...

The color inconstancy of prints is related to the ink spectral properties and the lookup table for multiink
printing systems. In this paper, color inconstancy was investigated for several ink-jet printers
based on their ink set and the default lookup tables. A virtual model for each printer was created to
determine the range of color inconstancy that a specific ink set could achieve. The color inconstancy
performance of each default lookup table was evaluated by evaluating the color inconstancy of a
printed test target. The optimum combinations of three- and four-chromatic inks were investigated to
minimize the color inconstancy and keep a relative large color gamut simultaneously. The results
showed that the color inconstancy can be decreased significantly without compromising the
reproduction colorimetric accuracy. Moreover the color inconstancy can be improved by appropriate
ink design.; "Exploring the color inconstancy of prints," Proceedings of the Tenth Congress of the International Colour Association. Held in Granada, Spain: 8-13 May 2005.; none

The use of colorimetry within industry has grown extensively in the last few decades. Central to many of today's instruments is the CIE system, established in 1931. Many have questioned the validity of the assumptions made by Wright1 and Guild,2 some suggesting that the 1931 color-matching functions are not the best representation of the human visual system's cone responses. A computational analysis was performed using metameric data to evaluate the CIE 1931 color-matching functions as compared to with other responsivity functions. The underlying assumption was that an optimal set of responsivity functions would yield minimal color-difference error between pairs of visually matched metamers. The difference of average color differences found in the six chosen sets of responsivity functions was small. The CIE 1931 2° color-matching functions on average yielded the largest color difference, 4.56 E. The best performance came from the CIE 1964 10° color-matching functions, which yielded an average color difference of 4.02 E. An optimization was then performed to derive a new set of color-matching functions that were visually matched using metameric pairs of spectral data. If all pairs were to be optimized to globally minimize the average color difference...

Standard color-matching functions are designed to represent the mean color-matching response of the population of human observers with normal color vision. When using these functions, two questions arise. Are they an accurate representation of the population? And what is the uncertainty in color-match predictions? To address these questions in the dual context of human visual performance and cross-media reproduction, a color-matching experiment was undertaken in which twenty observers made matches between seven different colors presented in reflective and transmissive color reproduction media and a CRT display viewed through an optical apparatus that produced a simple split-field stimulus. In addition, a single observer repeated the experiment 20 times to estimate intra-observer variability. The results were used to evaluate the accuracy of three sets of color-matching functions, to quantify the magnitude of observer variability, and to compare intra- and inter-observer variability in color-matching. These results are compared with various techniques designed to predict the range of color mismatches. The magnitude of observer variability in this experiment also provides a quantitative estimate of the limit of cross-media color reproduction accuracy that need not be exceeded. On average...

The prediction of color appearance using the RLAB color space has been
tested for a variety of viewing conditions and stimulus types. These tests
have shown that RLAB performs well for complex stimuli and not-so-well
for simple stimuli. This article reviews the various psychophysical results,
interprets their differences, and describes evolutionary enhancements to the
RLAB model that simplify it and improve its performance.; Article may be found at: http://www.cis.rit.edu/fairchild/PDFs/PAP03.pdf

When viewing images, the relative luminance of the surround has a
profound impact on the apparent contrast of the image. For this reason,
photographic transparencies intended for projection in a darkened room are
produced with an objective contrast substantially higher than that necessary
for optimum reproduction as prints viewed in an illuminated surround. The
dark surround causes the image elements to appear lighter and this effect is
stronger for darker colors resulting in a loss in perceived contrast. This effect
is also of great importance in device-independent color imaging since
resultant images might be observed in a wide variety of media and viewing
conditions. Research on psychophysical scaling of brightness and lightness
and the effects of background and surround relative luminance on lightness
and chroma is reviewed. The importance of this research for deviceindependent
color imaging systems is described along with the prediction of
these effects using the RLAB color-appearance model. Finally, experiments
testing the use of RLAB and other color-appearance models in cross-media
color reproduction applications are described.; RIT community members may access full-text via RIT Libraries licensed databases: http://library.rit.edu/databases/